Strapping apparatus



Robert J. Koblella Primary Examiner-Billy J. Wilhite Rolling Meadows,Ill. Auorney-Dressler, Goldsmith, Clement & Gordon [211 App]. No.748,698

July 30, 1968 Dec. 22,1970 Slgnode Corporation o o ation ofDehv mABSTRACT: An apparatus for providing a tensioned loop of strap about anobject wherein a carrier in slip feed engagement with a length of strapmoves the strap in a closed path around the object to form a closedtensioned loop having overlapping portions that are sealed to oneanother. The carriloolzs er is movable in opposite directions along theclosed path for 100/33; 156/73 fonning successive loops, and a singlesupply provides strap 365, 13/10 for the carrier in both directions ofits movement. A strap 100/23, 27, storage means is associated with thecarrier for accumulating 28 29 3O, 31, 32 3 3 strap during certainportions of the carrier movement, and for paying out strap during otherportions of the carrier move- Rgfgm CM ment. The strap sealing meansincludes an anvil that is mova UNITED STATES PATENTS ble between a firstposition in the strap path during the wrapping and sealing operation anda second position dis- 29 Clalns, 18 Drawing Figs.

77x8 7 Baum H mmflw m 11/1 1 m "H m w l" mm m "nan m mwa mmm "B m mm m Ya B flkG wnb m aao E r HvKLwG mam 9999 9 1111 ll/ 37 2 1 1 2362 6 3581 4awn. 0 7 2233 United States Patent [72] inventor 221 Filed 45 Patented[73] Assignee s41 s'rnAremo APPARATUS 51] in. so]

placed from the strap path allowing the strap to move into engagementwith the strapped object. The sealing means further includes a hammerthat is supported on a carriage which is movable to a position whereinspring means cause the hammer to compress the overlapped strap portionsagainst the anvil for a subsequent friction fusing operation.

PATENTED DEB22 I976 SHEET S []F 7 ill.

PATENTEDDEBZZISYD 3.648740 SHEET 7 0F 7 SZQ STRAPPING APPARATUSBACKGROUND OF THE INVENTION This invention relates to systems fordraping and tying a loop of strap about a package or other object to betied and, more particularly, the invention is concerned with a methodand an apparatus for effecting draping of a loop of strap completelyabout an object without need for a conventional strap chute or strapfeeding equipment.

It is frequently quite difficult to handle small lightweight steel orplastic straps in a conventional strap chute such as is normallyemployed for guiding such straps around bundles and packages. Thisdifficulty increases with the length of the chute.

In conventional strap feeding through a strap chute, it has provenextremely difficult to control accurately the amount of strap feedaround a chute so as to avoid both overfeeding and underfeeding.Frequently, delicate controls have been required to measure the amountof strap being fed through a conventional chute.

These problems encountered in the present day conventional equipment aregreatly aggravated by camber, curl and twist effects which are usuallypresent in lightweight metal and nonmetallic strapping.

SUMMARY OF THE INVENTION The present invention provides a system forovercoming these problems and for eliminating the conventional strapchute. For this purpose, a chain powered slip feed arrangement isprovided and includes a reversible movable carrier that follows agenerally rectangular chain loop that encircles a package tyingposition.

The chain driven draping arrangement is mechanically simple, making itparticularly useful for power strapping applications in plants whereonly a minimum of maintenance is available. Additionally, the slip feedarrangement eliminates the necessity of positively securing the bindingto the carrier member. Also, the reversible draping arrangement lendsitself to automatic cycling while utilizing only a single supply ofbinding material.

The anvil structure of the present invention has novel strap grippingmeans including a pair of gripping fingers, one of which is operativeduring carrier. movement in one direction to hold the leading end'of thestrap against the anvil, and the other of which is active duringmovement of the carrier in an opposite direction to hold the strapagainst the anvil. The anvil structure is normally disposed in the strappath during strap feeding and sealing operations, and the anvil isretractable to a position beyond the strap path after sealing iseffected, so that the sealed loop can snap into engagement with thestrapped object. A novel finger structure is associated with the anvil,so that the strap will be positively held in a clearance positionallowing the anvil to freely move into and out of the strap path.

The hammer structure of the present invention, which cooperates with theanvil to effect a friction-fusing operation of overlappingstrapportions, is mounted on a movable carriage assembly, and a cam controlstructure shifts the carriage to move the hammer into a positionwherein-spring means urge the hammer toward the anvil with apredetermined force to compress the overlapped strap portionstherebetween. The hammer is oscillated by a torsion bar sealingmechanism disclosed and claimed in the commonly assigned applicationSer. No. 735,842 filed June 10, 1968, which issued as Pat. No. 3,494,280on Feb. 10, I970.

Other features and advantages of the invention will be apparent from thefollowing description and claims, and are illustrated in theaccompanying drawings which show structure embodying features of thepresent invention, and the principles thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic front view ofa strapping apparatus utilizing a chain driven carrier for draping aloop of strap about a package, and showing the carrier at a startposition alongthe chain path in full lines and at various otherpositions therealong in broken lines;

FIG. la is a fragmentary diagrammatic view illustrating a modificationof the strap carrier tensioning and slack controlling structure;

FIG. 2 is a related fragmentary view showing the carrier pulling finaltension after a complete loop has been drawn about the package;

FIG. 3 is a related fragmentary view showing the carrier at the end ofits clockwise cycle and prepared for reverse travel;

FIG. 4 is a diagrammatic front view of the apparatus in the restposition immediately following sealing of the loop, and also showing thecarrier at various positions of its counterclockwise draping travel pathin broken lines;

FIG. 5 is a related fragmentary front levational view showing thecarrier pulling final tension for 'the counterclockwise drapingmovement;

FIG. 6 is a related fragmentary view showing the carrier at a reversepoint immediately prior to scaling of the second loop;

FIG. 7 is an enlarged fragmentary top plan view showing the arrangementof parts at the sealing station for the carrier positions of FIGS. 1 and2;

FIG. 8 is a front elevational view of the structure illustrated in FIG.7;

FIG. 9 is a transverse sectional view through the carrier station takenin the plane of the strap loop as indicated by the line 9-9 on FIG. 8;

FIG. 10 is a front view similar to FIG, 8 and showing the sealer in itsworking position which corresponds to the sequence view of FIG. 3;

FIG. 11 is a fragmentary sectional view similar to FIG. 9 but showingthe parts in a position at a time immediately prior to the positionshown in FIG. 4, this position being the presealing cocked hammerposition;

FIG. 7a is a fragmentary top plan view similar to FIG. 7, and showingthe parts in the-position assumed at a time between the positions shownin FIGS. 3 and 4;

FIG. 7b is a top plan view, similar to FIGS. 7 and 7a, and illustratingthe parts in the position assumed at full anvil retraction, after theposition of FIG. 7a;

FIG. 8a is a fragmentary front view similar to FIG. 8, and showing theparts in a position at a time that corresponds to a position just priorto FIG. 4; and

FIGS. Ila, b and c are fragmentary sectional sequence view showing,respectively, the release of the completed loop from the anvil, thesnubbing of the strap about the anvil, and the cutting of the formedloop from the remainder of the strap.

DESCRIPTION OF THE PREFERRED EMBODIMENTS General Operation the presentdisclosure is to be considered as an exemplification of the principalsof the invention and is not intended to limit the invention to theembodiment illustrated. The scope of the invention will be pointed outin the appended claims.

Referring now to the drawings, the general arrangement and sequence ofoperation of the chain driven draping arrangement can best be tracedwith reference to FIG. I to 6. The apparatus includes main framingdesignated generally at F which provides a generally rectangularlyshaped window W for receiving the package P which is to be strapped. Asupport structure underlies the bottom of the window, and as isillustrated hereinafter, the support structure provides a guideway Gwhich receives the opposite ends of the strap loop that is being formedabout the package. The main framing F mounts a set of sprocketlikerollers Sl--S8 which have a chain 3 trained thereabout, as illustratedin FIG. II, the chain being a multiple strand type (FIG. 7) so that onestrand 3a engages the sprocket teeth and the other strand 3b rides freeadjacent to the sprockets. There are upper comer sprocket rollers S1 and'82 about and outboard each side of the window W and there are two setsof three vertically staggered sprocket rollers S3, S4, S and S6, S7, S8adjacent and beneath each of the lower comers of the window. The rollerstrand 3b includes a strap carrier C as an intermediate segment thereofand the carrier includes spaced rollers Cl and C2 defining a pass regionfor the strap. The support structure includes an anvil ll arranged toreceive the free end of the strap in underlying relation and a sealer 9is shown positioned beneath the anvil l for movement in working positionafter an overlapping strap layer is formed beneath the free end uponcompletion of the strap draping and tensioning movement of the carrier.Grippers 2 are shown flanking the anvil l to engage the free end of thestrap for holding strap tension.

The strap suppiy arrangement illustrated herein includes an infeedroller RI and a pair of intermediate rollers R2 and R3 which areoperable to set and control the back tension acting upon the strap. Thesupply arrangement includes a section capable of conveniently storingslack in preparation for draping about the package, for paying out theslack from storage to permit the back rollers R2 and R3 to set thetension and for taking up slack which accumulates during the tensiondrawing operation of the main chain 3. The storage section includes aslack takeup roller chain 3' trained about sprocket rollers S9 and whichare spaced apart vertically a distance sufficient to provide therequired storage capacity. The line of strap leading from the backtension rollers R2 and R3 extends between a pair of infeed guide rollersR4 and R5 bordering the left hand side of the takeup chain 3, through acarrier C which operates exclusively along the left hand run of thetakeup chain 3, through a carrier C" which operates exclusively alongthe right hand vertical run of the takeup chain 3, through a pair ofoutfeed rollers R6 and R7 bordering the right hand side of the takeupchain 3', around an upper corner roller R8 and through a pair ofcentering rollers R9 and R10 midway across the top of the window whichallow for feed of the strap in either wrapping direction about thepackage.

FIGS. 1, 2 and 3 are sequence views illustrating the operation of thechain during a clockwise draping movement. At the beginning of thecycle, as shown in FIG. I, the free end of the strap is fixedly heldagainst the right side of the anvil 1 by the right-hand gripper 2, and alayer of the strap underlies the anvil in contacting relation and leadsthrough the carrier C and around the upper left hand sprocket S1 to theentry rollers R9 and R10 that overhand the center of the window. Acommon drive motor (not shown) directly powers the lower left handsprocket S8 for advancing the carrier chain in a clockwise traveldirection to move the carrier successively from the full line positionto the successive phantom line position illustrated at the top and thenat the lower right-hand side of the chain travel path in FIG. 1, itbeing understood that the other sprockets are idlers which guide thechain.

An intermediate chain 3" is connected to drive a slip clutch associatedwith the lower sprocket S9 of the slack takeup mechanism to move theslack takeup chain 3' in a clockwise direction and accumulate strap fromthe main loop during the first half of the travel of the carrier, thatis, when carrier C moves up to the region of the centering rollers R9and R10. In the modification of FIG. la, the intermediate chain 3" andslip clutch associated with pulley S9 is eliminated, and instead, thehub of sprocket S9 is rotatable against the bias of a torsion spring TS,which controls movement of the takeup chain 3' in a manner similar tothe previously mentioned intermediate chain 3" and slip clutch.

During the next portion of the carrier travel, i.e. as the carrier Cmoves to the broken line position of FIG. 1 at the lower right-hand sideof the package, strap is paid out from storage so that the storagecarriers C and C" return approximately to the position illustrated inFIG. I, it being understood that the slip clutch associated withsprocket 59 allows the direction of travel of chain 3 to reverse. Duringfurther travel of the carrier C through the path to the positionillustrated in FIG. 2, the slack carriers C and C" come into registrywith the infeed rollers R4 and R5 and outfeed rollers R6 and R7, so thatall of the accumulated slack has been paid out and any continued travelof the carrier requires direct pay out of the strap from the supply reel(not shown). Therefore, during the phase of the travel when the loop isbeing completed and the second overlapping strap layer is being formedbeneath the anvil l and tension is drawn on the loop, the back tensionrollers R2 and R3 are operative to determine the value of the tension.

It may be noted that as the carrier 3 moves over the undulation in thecarrier path created by'sprocket S7 (FIG. 2), the line of strap beingwrapped across the bottom of the package P is shifted up the sealer 9 toa location next to the gripped strap end. After the strap is above thesealer 9, the sealer is shifted from the position of FIG. 2 toward theworking position of FIG. 3, and when the sealer reaches the workingposition, it holds the strap against the back tension while the carrierC continues to its reversal point shown in FIG. 3.

When the reversal position of FIG. 3 is reached, suitable switch means(not shown) is actuated to reverse the drive motor and rotate sprocketS8 and chain 3 in a counterclockwise direction. Chain 3" and sprocket S9are also rotated in a counterclockwise direction to rotate chain 3' in acounterclockwise direction and take up the slack induced by the reversemovement of carrier 3. Sealing occurs between the reversal point shownin FIG. 3 and the position shown in FIG. 4, and it should be noted thatin FIG. 4, the anvil I has shifted backwardly, or into the paper asviewed therein, so that the completed joint snaps up against theunderside of the package, after which the anvil returns to its projectedposition wherein it intercepts the plane of the strap loop but islocated now beneath the completed joint. As the carrier C moves towardthe FIG. 4 position, the strap is being snubbed about the left hand sideof the anvil 1 and the left hand gripper 2 comes into play to the strapportion adjacent the sealed joint against the side of the anvil 1. Atthis time, a cutter, as is described later, severs the completed straploop from the newly gripped strap and the device is now ready to drape aloop of strap in an opposite direction about the package.

During further travel of the carrier C in the counterclockwise drapingdirection from the position of FIG. 4, slack is being accumulated in thestorage section up to the time that the main carrier reaches thecentering rollers r9 and R10, and upon further travel, slack is payedout from the storage section so that by the time the carrier C hascompleted the formation of the loop and reaches the position shown inFIG. 5, the slack carriers C and C" are aligned with the infeed rollersR4 and R5 and outfeed rollers R6 and R7, so that the strap is being feddirectly from the supply to the back tension R2 and R3 rollers and upthrough the centering rollers R9 and R10. The tension of the strap loopis thus determined by the back tension of rollers R2 and R3. Once again,the section of strap being wrapped beneath the bottom of the packagerises above the sealer 9 to move into overlapping relation between thesealer 9 and anvil 1, and as the carrier C continues its travel to theFIG. 6 position, the sealer 9 moves up to working position. FIG. 6 isthe reversal position and during subsequent movement'of the carrier C ina clockwise direction, the sealing of the joint is completed and theanvil l retracts to permit the joint to snap up against the package Pand allow the succeeding portion of strap to snub about the anvil 1 forthe beginning of a further clockwise draping movement. I

From the foregoing, it will be apparent that with the free end of thestrap clamped by right hand gripper 2, as is shown in FIG. 1, agenerally open strap loop is formed between the right hand gripper 2 andthe carrier member C"with the right portion of the open loop beingdisposed adjacent roller R9. As the carrier C moves from the full lineposition of FIG. 1 to the first broken line position, carrier Cessentially travels along one reach of the aforedescribed open loop,causing the reach to conform to the configuration of the package P asthe carrier C moves between sprocket S1 and rollers R9 and R10. As the,

carrier C passes rollers R9 and R10, and completes its travel around thepackage P, the bight portion of the aforedescribed open loop is pulledaround the package, with the inner reach of the open loop conforming tothe package and the outer reach of the open loop traveling with thechain 3. By pulling the bight portion of the open loop around thepackage P, an inner reach is provided for sealing to the gripped end ofthe strap, and an outer reach is provided for subsequently wrappingaround a further package, when the direction of carrier movement isreversed. The sets of clustered rollers S3, S4, S5 and S6, S7, S8function to enlarge the bight portion of the open loop, so that theinner reach can pass closely adjacent to the anvil 1, while the outerreach remains in a clearance position. The sprocket S7 functions toposition the inner reach closely adjacent to the anvil l as is evidentfrom FIG. 2 during clockwise movement, while sprocket S4 functions toposition the inner reach closely adjacent to anvil 1 during acounterclockwise movement, as is event from FIG. 5.

Detailed Description of Operation The operation station is centeredalong the lower reach of the main carrier chain 3 and includes a sealersection and a gripper and cutter section spaced on opposite sides of theplane of the strap loop to define guideway gap G for reception of thestrap.

A common drive (FIG. 8 and 9) for timing the operation of the movingparts in these sections is located therebeneath and is synchronized withthe movement of the carrier chain 3 as is described in detail herein.The drive includes a main cam shaft 4 that is supported in suitablebearings (not shown) on the main frame, and shaft 4 is reversiblyoperable by the same motor which moves the carrier chain 3. A bifurcatedcocking cam 5 and a barrel cam 6 are coaxially arranged on the cam shaft4, and cam 5 has a rearwardly extending drive pin 7 operating inlost-motion relation in a drive slot 8 in the front face of barrel cam6.

j The cam shaft 4 controls the actuating and timing of a number ofrelated mechanisms. For example, a cam arm 34 FIGS. 8, 8a and 10) ispivoted at 3411 to ride with a flange portion of the cam shaft 4 toswing past a position for operating a gripper and cutter actuation arm35 that is swingable about a pivot 36 in the support housing of thegripper and cutter section. The cocking cam 5 has spaced tips 5a and 5b(one for each strap draping direction) that rotate to crank and thenrelease a trigger arm 16 for operating. the sealer. The barrel cam 6 hasa cam slot 6c between flanges 6a and 6b that receives a cam follower 11carried by a pressure arm 12 that regulates the positioning of a sealercarriage 15.

The pressure arm 12 and sealer carriage are swingable about a commonaxis defined by a shaft 13 which is supported in the housing structure.A preload stop screw 17 FIGS. 8 and 10) is threaded through the rear ofthe sealer carriage 15 for engagement with the pressure arm 12 to setits bias relation with respect to a pressure spring 14 that reactsbetween the pressure arm 12 and sealer carriage 15. In this respect itwill be noted from FIGS. 8 and 10 that the rearward end of spring 14 isconfined within a forwardly facing socket 12a in the front face ofpressure arm 12, while the forward end of spring 14 is confined within arearwardly facing socket 15a in carrier 15. The rear of the sealercarriage 15 provides a rigid socket mount 23 that anchors one end of atorsion bar 22 which extends full length through the carriage 15 toreceive a hammer 9 in keyed relation on its free forward end. Thetrigger arm 16 is joumaled in the carriage l5 and supports the torsionbar 22 in drivingly keyed relation along an intermediate position.

Thus the sealer carriage l5, pressure arm l2, torsion bar 22, trigger l6and hammer 9 are swingable as a unit about the axis of the shaft 13between the rest position shown in FIGS. 8 and 9 and the sealingposition shown in FIGS. 10 and 11. This movement is controlled by thepressure arm 12 which is positioned in accordance with the rotaryposition of the barrel cam 6, with the workingpressure of the hammer 9that holds the overlapping strap ends against the anvil 1 beingdetermined by the spring 14.

The anvil l is normally biased to a position projecting through theplane of the strap loop by means of a spring 28 (FIGS. 7 and 7b)reacting between the sealer section framing and an anvil abutment la,but return movement of the sealer carriage 15, that is, from FIG. 10 toFIG. 8 retracts the anvil, as will be hereinafter explained, to allowthe sealed strap joint to move about the anvil 1 and against thepackage, thereby freeing the finished loop'from the strapping machine.

As shown in FIGS. 1, 2, 3 and 9, the free strap end is pinched betweenthe upright right hand side of anvil l and the right hand gripper 2,with the strap passing under the anvil 1 to the left to lead in aclockwise direction around the package P. The strap passes through thechainlike carrier C and through the remainder of guide and snubberrollers Rl-Rl0 as shown in FIG. 1.

' During the clockwise strap wrapping cycle, the motor drives thecarrier C and cam shaft 4 in a clockwise direction, as viewed in FIGS. 1and 9. The cam shaft 4 drives the cocking cam 5 which drives the barrelcam 6 through the engagement of pin 7 with the end of the lost-motionslot 8. The carrier C pulls the strap around the package as shown by thebroken line sequence positions in FIG. 1.

When the strap has passed completely around the package, as shown inFIG. 2, and has slid up along the hammer 9, it is located in propersealing position, due to the undulation in the carrier path defined bysprocket S7. As cam shaft 4 and cam 5 continue to rotate in a clockwisedirection, the barrel cam 6 reaches a position which causes a rampportion 10 (FIG. 10) on flange 6b to contact the cam follower l! at thelower end of pressure arm 12. Further motion of the carrier C and camshaft 4 in the clockwise direction (ultimately ending in position shownin FIG. 3) causes the cam follower 11 to rotate the pressure arm 12counterclockwise about axis 13 to apply pressure to spring 14. Thespring 14 rotates the sealer carriage 15, to which is mounted the swinghammer .9 and the trigger l6, counterclockwise.

Near full travel of the cam follower 11 brings the swing hammer 9 intocontact with the two layers of strap squeezing them against the anvil 1.As the cam follower 11 reaches its full travel, the pressure on thestraps between the hammer and anvil will exceed the rateof the pressure'spring 14 causing the sealer carriage 15 to stop rotating and furthercompress the spring, thereby effecting a controlled pressure at thestraps interface. This allows the pressure arm 12 to advance slightlypulling away from the stop screw 17. The screw 17 reduces unnecessarypressure spring preload travel. When the cam follower 1 l is at its fulltravel, the machine is at its reversal point, and a limit switch (notshown) is actuated by the cam shaft 4 which causes the motor toimmediately reverse.

At reversal, the cocking cam 5 has been rotated to assume a verticallycentered symmetrical position beneath the trigger 16. As the sealercarriage l5 swings up into working position, it carries trigger 16 alongwith it, and the trigger swings up in between the cocking cam teeth 54and 55, being synchronized by proper spacing of the teeth to preventinterference. As the drive chain C reverses, the strap tends to go slackbut the tension pulled on the strap convolution surrounding package P isretained by the interface pressure applied against anvil l by hammer 9.The motor reversal also reverses cam shaft 4, causing it to rotatecounterclockwise.

During counterclockwise rotation of shaft 4, the pin 7 attached to thecocking cam 5 initially rides free in the slot 8 of the barrel cam 6allowing the barrel cam to remain stationary while the cocking camrotates relative to it. As the cocking cam 5 rotates, its trailing tooth5b contacts the trigger l6 pivoting it in a clockwise direction aboutthe axis of torsion bar 22 to the position at FIG. 11. The trigger,through a positive drive socket 21, twists the torsion bar 22, which hasits rear end securely fastened in the rear socket 23 to prevent rotationof the rear end. The trigger 16 also drives the swing hammer 9 to theposition shown in FIG. 11, and the swing hammer 9 slides the outside orlower strap layer over the inside or upper strap layer due to teeth onits contact surface. The strap moves in a direction to slacken thetension on the package.

The cooking cam tooth b continues rotating the trigger 16 untilultimately it releases the trigger. At this instant, the torsion bar 22has stored the necessary energy (500-750 inchpounds of torque for aone-fourth inch strap) to make a joint by the bodily slidingfriction-fusion technique such as is described in Stensaker et al.application Ser. No. 479,446, filed Aug. 13, 1965 now US. Pat. No.3,442,732 which issued May 6, 1969. The releasing of the trigger 16 bythe cocking cam tooth 5b allows the torsion bar 22 to return to arelaxed state being impeded only by the frictional force at the strapsinterface and whatever small resistance the remaining strap tension andmounting bearings offer. The torsion bar 22 has more energy stored thanthe resistances offer, therefore, it oscillates very rapidly as apendulum for a few cycles until substantially all the stored energy hasbeen transferred to heat energy. The heat is mainly concentrated at thestraps interface regions, which melts the plastic material the strap ismade of.

After the straps surfaces are molten, the pressure applied by the hammer9 is retained long enough to solidify the plastic material therebyeffecting a securely fused joint. As the joint is fusing, pin 7 in thecocking cam 5 moves into engagement with the end of the slot 8 in thebarrel cam 6 to rotate the barrel cam in a counterclockwise directionand move its cam surfaces to allow the cam follower 11 to start back toits initial position.

The pressure spring 14 swings the pressure arm 12 back until it contactsthe stop screw 17. Further travel is imparted to the arm by a returnramp 6d (FIG. of the barrel cam flange 6a. The pressure arm 12 actsagainst stop screw 17 to swing the sealer carriage l5 clockwise aboutshaft 13, and the sealer carriage pulls the swing hammer 9 down awayfrom the straps.

Generally D-shaped finger carriages 19 (FIG. 7) are mounted alongopposite sides of the sealer section to rotate about pivot pins 27carried in fixed outboard lug portions 19L. When the finger carriagesare in their rest position as shown in FIG. 9, rollers 18 on thedepending lower ends of the finger carriages are nested withindownwardly opening slots 158 (FIG. 8) of the sealer carriage so thatupward swinging movement of the carriage towards working position earnsthe rollers 18 to shift the finger carriages forwardly or to the rightas viewed in FIG. 7, to a position where the finger portions projectinto the plane of the strap path for interference with the strap asshown at the left in FIG. 11.

When the strap is raised to the level shown in FIGS. 2, 3 and 9, fingerabutment 20 is spaced rearwardly of the strap path, so that the strap isfree to move to the rest position elevation above the finger portion 20.The abutment 20 on the left hand finger 19 thereafter shifts forwardlyduring upward swinging I movement of the carriage 15 to a position belowthe strap. Now with the carrier chain moving counterclockwise, it pullsthe supply strap back down to wrap around left hand finger abutment 20as shown in FIG. 11. Tension reactions of the strap cause the left handfinger 20 to pivot the left hand finger carriage 19 clockwise about axis27. The left hand finger carriage thereby brings its left hand shipperfinger 29 into contact with a left hand return finger (FIG. 7a.

As the sealer carriage 15 is fully raised into sealing position, that isfrom FIG. 8 to FIG. 10, a link 24, which has one end connected to theupper forward portion of carrier 15, is pushed up. The other end of link24 is connected to a pivotally mounted release pawl 25, and upwardmovement of link 24 rotates release pawl 25 in a clockwise direction. Arelease catch 26 is pivotally mounted above and to one side of pawl 25,and a tang 25a on pawl 25 rotates release catch 26 counterclockwiseuntil the tang 25a moves past a catch tang 26a on release catch 26. Afoot 25b on pawl 25 kicks another tang 26b on catch 26 to return thecatch to its initial position. The sealer carriage 15 during returnmovement clockwise, that is, from FIG. 10 to FIG. 8, pulls the link 24down to rotate release pawl 25 counterclockwise. Release pawl tang 25acontacts the release catch tang 26a to rotate release catch 26clockwise, but the release catch 26 contacts a stop pin 31 in anvil 1which stops rotation of the release catch. The locked release catch 26is then forced back carrying the anvil l and compressing the returnspring 28. When the pawl 25 has rotated nearly its full travel, tang 25amoves out of engagement with catch tang 26a to release catch 26, and thereturn spring 28 forces the anvil 1 back to its strap engaging position.

The rotation of the cam shaft 4, simultaneously with causing return ofthe sealer carriage 15, brings cam surface 32 on arm 34 into contactwith cam follower 33 to swing arm 35 from the FIG. 8 to the FIG.position. A cam art stop pin 32? (FIG. 8a) is arranged so that the camarm 34 is free to pivot in one direction only about an axis 34A so as tobypass the cam follower 33 when the cam shaft, 4 was rotating clockwise,as viewed in FIG. 9. The cam follower 33 causes gripper and cutteractuation arm 35 to rotate clockwise about pivot shaft 36, and anabutment 350 at the upper end of arm 35 contacts a pin 37 to drive agripper and cutter carriage 38 to the right against spring 39. A guiderod 47 is fixed to carriage 38 and extends through spring 39 and through.a suitable opening in the support frame.

Pins 41 extend upwardly from gripper and cutter carriage 38 throughelongated slots 20 in grippers 2, and as arm 35 moves carriage 38 to theright from the position of FIG. 7 toward the position of FIG. 7b,carriage 38 moves pins 41 back until the pins contact the end of thegripper slots 2a. Pins 42 are fixed relative to the machine frame, andthe inner ends of grippers 2 are pivotally mounted on pins 42, so thatfurther motion of carriage 38 to the right causes the grippers 2 torotate about pins 42, pulling the gripping arms 2b out of the strappath, as shown in FIG. 7b, with the right hand gripper 2 therebyreleasing the strap. A cutter blade 40 is attached to the carriage 38and is also pulled back out of the strap path as the carriage isretracted by actuation arm 35. The action of retracting the grippers 2is timed to occur prior to the full retraction of the anvil 1.

When the anvil 1 is near its full retraction, the fused straps arereleased to freely snap out from under the anvil. At this time, fi gers20 remain in the strap path and the strap from the supply reel is stillwrapped around the left hand finger 20 in a fashion to spread the strapsto straddle the anvil path, as shown in FIG. 11a. This insures that theanvil will return between the fused straps and the supply strap as itmoves forwardly. As the anvil 1 is retracting, it moves upright pins 43at the rearward end of the anvil to cause left hand return finger 30 toswing about a fixed pin 44, it being understood that slots 44a infingers 30 allow the fingers to move longitudinally relative to theanvil. At a stroke just short of full anvil retraction, the end of theleft hand return finger 30 has moved from the position of FIG. 7a to theposition of FIG. 7b out of contact with left hand finger carriageshipper finger 29. This allows the back tension of the supply strap,which is wrapped around left hand finger 20, to pivot the left handfinger carriage 19 inwardly to its full travel. This moves the left handshipper finger 29 rearwardly to the left hand return finger 30, as isillustrated in FIG. 7b.

When the anvil l is released and returned to strap engaging position(FIG. 11b) it pulls pins 43 with itself to rotate the return fingers 30back to their initial position, but since the left hand shipper finger29 now lies in the path of the left hand return finger, the left handreturn finger contacts the left hand shipper finger 29 pushing it to theleft from the position shown in FIG. 7b. The left hand shipper finger 29moves the left hand finger carriage 19 and the left hand finger 20 backout of the strap path releasing the supply strap, as is shown in FIG.11b. The left hand finger carriage 19 is now free to rotate back to itsinitial position, as shown in FIG. 7. The back tension of the supplystrap takes up the slack caused by the retraction of the left handfinger 20, and the supply strap now pulls up to wrap around the extendedanvil, as shown in FIG. 11b. Shortly after the supply strap is snubbedaround the anvil, as shown in FIG. 110, the cam arm 34 rotates out fromunder cam follower 33 to allow the gripper and cutter carriage 38 to bepushed back to its initial position FIGS. 7 and 8) by spring 39.

When the carriage 38 was pulled backinitially (FlG.'7b) and pins 41contacted the end of the gripper slots 2a, ramps 2c on grippers 2 moveinto contact with gripper advance plungers 45 in carriage 38 to forcethe plungers 45 back compressing springs 46. Now when the carriage 38 isreturning and pins 41 tend to travel to the other end of the gripperslots 2a, the springs 46 force plungers 45 to follow the ramps 20, thuskeeping the same end of the gripper slots 2 in contact with the pins 41.This, in turn, allows the grippers 2'and their arms 2b to be in anadvanced position relative to pivot pins 42. The cutter 40, beingattached to the carriage 38, is also moved toward its initial positionand contacts the edge of the supply strap which is now snubbed aroundthe anvil 1, as shown in FIG. 110. The spring 39 exerts the forcerequired to cut the strap at a plane just above the top of the anvil.

As the cutter blade 40 is being driven through the supply strap, theadvanced position of the left hand gripper 2 causes its arrn 2b tocontact the portion of the supply strap just below the top of theanvil 1. This occurs before the blade 40 has completely severed thesupply strap. The left hand gripper 2 stops rotation and the pin 41leaves the back of the slot 2a. This allows the spring 46 to impart itsforce through the plunger 45 against the ramp to supply a small pinchingforce by the left hand gripper arm 2b on the supply strap against theanvil 1. At this time, the back tension on the supply strap is light.The carriage 38 continues its advancement causing the cutter tocompletely sever the strap. When the carriage 38 nearly completes itstravel, the pins 41 contact the other end of the gripper slots 2a. Thespring 39 then imparts its force through the pins 41 to cause the lefthand gripper 2 to apply a large pinching force against the strap. Thisforce is sufficient to hold the strap when high tensions are pulledduring the wrap cycle. A switch is tripped by the mechanism to stop themotor. 1

The machine is now ready for another cycle but in the opposite, i.e.,counterclockwise, wrap direction. It may now be noted that the righthand finger carriage 19 was returned to its initial position when thesealer carriage 15 returned to its initial or rest position since therewas no strap to rotate its roller 18 out of engagement with the sealercarriage slot 155.

It will be readily observed from the foregoing detailed description ofthe invention and in the illustrated embodiments thereof that numerousvariations and modifications may be effected without departing from thetrue spirit and scope of the novel concepts and principles of thisinvention.

1 claim:

1. Apparatus operative upon a length of flexible binding having a freeend and a supply end for fonning a loop of binding material about anobject comprising:

carrier means in skip feeding engagement with a portion of said bindingbetween said free end and said supply end; means for engaging andholding the free end of said binding; interengaging chain and sprocketmeans for moving said carrier means along a closed path around saidobject to transport said binding around said object and form a loophaving overlapping regions;

further chain and sprocket means for taking up slack in said bindingduring a portion of the movement of said carrier means and for payingout slack during a further portion of the movement of said carriermeans;

means for sealing said overlapping regions to one another;

and means for severing said loop from said supply end.

2. Apparatus as set forth in claim 1 wherein said carrier means isdefined by at least one pair of spaced rollers associated with saidchain means, said binding being freely interleaved between said spacedrollers.

3. Apparatus for compressing and sealing overlapping strap portionscomprising:

an anvil having a strap engaging surface;

carrier means including an actuator;

a hammer mounted on said carrier means and having a strap engagingsurface;

means for oscillating said hammer relative to saidcarrier meansincluding an actuator at a fixed location; and

means mounting said carrier means for movement between a first positionwherein said hammer is spaced from said anvil and said carrier memberactuator is spaced from the actuator at said fixed location, and asecond position wherein said hammer surface is positioned in juxtaposedrelationship with respect to said anvil surface to compress saidoverlapping strap portions against one another'with a predeterminedamount of force and to locate said carrier member actuator in operativeassociation with the actuator at said fixed location.

4. Apparatus for compressing and sealing overlapping strap I portionscomprising:

an anvil having a strap engaging surface;

carrier means including an actuator;

a hammer mounted on said carrier means and having a strap engagingsurface; means for oscillating said hammer relative to said carriermeans including an actuator at a fixed location and a torsion bar havingone end fixed to said carrier means and the other end connected to saidhammer, said carrier member actuator being a trigger fixed to saidtorsion bar and having an abutment thereon, and said other actuatorbeing a cocking cam having at least one abutment thereon engageable withsaid trigger abutment to stress said torsion bar; and f means mountingsaid carrier means for movement between a first position wherein saidhammer is spaced from said anvil, and a second position wherein saidhammer surface is positioned in juxtaposed relationship with respect tosaid anvil surface'to compress said overlapping strap portions againstone another with a predetermined amount of force and to locate saidcarrier member actuator in operative association with the actuator atsaid fixed location.

5. Apparatus as set forth in claim 4 wherein said cocking cam-has a pairof spaced abutments engageable with said trigger abutment for stressingsaid torsion bar upon movement of said cam in either of two oppositedirections.-

6. Apparatus as set forth in claim 5 wherein said cam is mounted forrotation with a cam shaft, with the rotation of said cam shaft'beingsynchronized with-the carrier member movement so that said triggerabutment is positioned between said cam abutments when said hammer is insaid second position.. 2

7. Strap gripping apparatus comprising:

an anvil;

a carrier mounted for movement between a first position adjacent saidanvil and a second position removed therefrom;

means biasing said carrier toward said first position;

a gripping finger mounted for pivotal movement relative to said anvilbetween an active strap gripping position and an inactive strapreleasing position means on said carrier for moving said'gripping fingerfrom active to inactive position upon movement of said carrier from saidfirst to said second position, and for moving said gripping finger frominactive to active position upon movement of said carrier from second tofirst position;

and means for moving said carrier against said biasing means from saidfirst to said second position.

8. Apparatus as set forth in claim 7 wherein said gripping fingerincludes a slot, and wherein said carrier member means includes anabutment received in said slot for effecting controlled movement of saidgripping finger between said active and inactive positions.

9. Apparatus as set forth in claim 8 wherein said slot has a dimensionlarger than said abutment whereby a lost motion connection is providedbetween said gripping finger and said carrier, and wherein said carrierincludes means for retaining said abutment at one end of said slotduring movement of said finger from inactive to active position so thatsaid gripping finger will reach active position before said. biasingmeans returns said carrier to said first position.

10. Apparatus as set forth in claim 9 wherein said last mentionedretaining means includes a plunger movable relative to said carriage,and spring means biasing said plunger into engagement with said grippingfinger.

11. Apparatus as set forth in claim 10 wherein identical gripping fingerstructures are provided at opposite sides of said anvil for use inapparatus for forming successive strap loops by feeding strap inopposite direction.

12. For use in apparatus for draping a strap loop about an object andfor sealing overlapped end portions of the strap at a sealing station,an anvil structure comprising:

an anvil mounted for movement between a first position at said sealingstation and a second position removed therefrom;

means urging said anvil into said first position during strap drapingand sealing operations;

carrier means a hammer on said carrier means and movable toward saidanvil when said anvil is in said first position for compressingoverlapped strap portions therebetween; and

means for moving said anvil to said second position when a sealingoperation is completed, said anvil moving means being conditioned foractuation by movement of said hammer toward said anvil.

13. The invention set forth in claim 12 wherein said anvil structurefurther includes a first gripping means for retaining a strap endagainst said anvil during a first strap draping and sealing operation; asecond gripping means for retaining a further strap end against saidanvil during a second strap draping and sealing operation; and commonmeans for moving said first and second gripping means between a grippingposition and a release position.

14. The invention set forth in claim 12 in which said hammer is movableaway from said anvil to a rest position when a sealing operation iscomplete and wherein the means for moving the anvil to second positionincludes an abutment on said anvil and a cooperating abutment on saidcarrier means engaging said anvil abutment upon movement of said hammertoward said rest position.

15. The invention set forth in claim 14 wherein said carrier abutmentmoves out of engagement with said anvil abutment before said hammerreaches the rest position, whereby said urging means moves said anvil tofirst position.

16. The invention set forth in claim 15 in which said carrier abutmentis a catch pivotally mounted on said carrier means and having anabutment surface engaging said anvil abutment, and wherein a releasepawl is pivotally mounted on said carrier means for moving past saidcatch during movement of said hammer toward said anvil to condition saidcatch for moving said anvil to said second position as said hammer movestoward said rest position.

17. Apparatus for gripping and retaining strap portions in overlappingrelationship comprising:

an anvil having a strap engaging surface;

a hammer having a strap engaging surface; and

means for moving said hammer relative to said anvil to compressoverlapping strap portions between said strap engaging surfacesincluding, carrier means having said hammer thereon, means mounting saidcarrier means for movement between a first position wherein said hammeris spaced from said anvil and a second position wherein said hammersurface is positioned in juxtaposed relationship with respect to saidanvil surface, regulating means mounted for movement relative to saidcarrier means, and means biasing said carrier means outwardly of saidregulating means for urging said hammer surface toward said anvilsurface to compress said overlapping strap portions against one anotherwith a predetermined amount of force.

18. Apparatus as set forth in claim 17 wherein said mounting meansincludes a shaft pivotally supporting said carrier means.

19. Apparatus as set forth in claim 18 wherein said regulating meansincludes a pressure arm pivotally mounted on said shaft, said biasingmeans being defined by a spring acting between said pressure arm andsaid carrier means.

20. Apparatus as set forth in claim 19 wherein said pressure armincludes a cam follower thereon, and wherein said hammer moving meansincludes cam means engageable with said cam follower.

21. Apparatus as set forth in claim 29 including means for adjusting theposition of the pressure arm relative to the carri- 22. Apparatus as setforth in claim 21 wherein said cam is shaped to move said pressure armaway from said adjusting means in the second position of said hammer,whereby said pressure arm compresses said spring to thereby compresssaid overlapped strap portions with said predetermined force.

23. Apparatus for compressing and sealing overlapping strap portions ina strap path comprisingi first and second members for compressingoverlapping strap portions therebetween, said first member being ananvil having a strap engaging surface and said second member being ahammer having a strap engaging surface; means for effecting relativemovement between said first and second members between a spaced positionand a strap compressing position, said relative movement effecting meansincluding movable carrier structure supporting said hammer for bringingsaid hammer surface into juxtaposition with said anvil surface tocompress the overlapping strap portions therebetween;

strap holding means; and

means responsive to said relative movement for moving said strap holdingmeans between an inactive position spaced from said strap path and anactive position in the plane of said strap path for holding a furtherportion of the strap adjacent said overlapped portions,said means formoving said strap holding means including cooperating abutments on saidcarrier structure and said strap holding means.

24. Apparatus as set forth in claim 23 wherein said holding means isdefined by an arm having an intermediate portion mounted for pivotalmovement, with one of said abutments being provided at one end of saidarm and with a strap holding finger being provided at an opposite end ofsaid arm, said finger being adapted to pivot said arm when said furtherportion of strap is wrapped therearound.

25. Apparatus as set forth in claim 24 wherein a pair of.

identical arms are provided at opposite sides of said anvil forperforming 'strap holding functions during successive strapping cycles.

26. Apparatus as set forth in claim 25 including means mounting saidanvil for movement out of said strap path after a sealing operation iscompleted, said holding means further including means responsive tomovement of said anvil out of said strap path for moving the abutment onsaid pivoted arm out of said strap path.

27. Apparatus as set forth in claim 26 wherein said holding meansincludes a stop that is positioned by pivotal movement of said arm, andwherein said anvil includes a shifting link engageable with said stopfor effecting return movement of said holding means.

28. Apparatus as set forth in claim 27 wherein said link has an abutmentat one end engageable with the holding means stop, the opposite end ofsaid link being pivotally connected to said anvil and an intermediateportion of said link being connected to said anvil by a lost motionguide means.

29. Apparatus as set forth in claim 25 in which said fingers arealternately operative during successive strapping cycles, thenonoperating finger being moved between said active and inactivepositions by said cooperating abutments, and wherein means is providedon said anvil for moving the operating finger from active to inactiveposition upon movement of said anvil out of said strap path.

